Effects of Hepatocyte Growth Factor on Rat Inflammatory Bowel Disease Models

Hepatocyte growth factor (HGF) is a hepatotrophic factor and, also, functions as an epithelial growth factor. We examined the therapeutic effects of HGF on rat inflammatory bowel disease models induced by trinitrobenzensulfonic acid or dextran sulfate sodium. Recombinant human HGF was continuously administered at 50 g/body/day using an intraperitoneally implanted pump for 7 days. Treatment of HGF reduced the ulcerated area, histological damage score, mucosal myeloperoxidase activity, and epithelial apoptotic rate but did not increase epithelial mitotic rate and immunohistochemical labeling indexes of proliferating cell nuclear antigen, Ki-67, and bromodeoxyuridine as indexes of epithelial cell proliferation in either model. We then examined the epithelial localization of the HGF receptor c-met and identified it on the surface epithelia, where apoptosis was observed, but did not find it in the proliferative zone. These results suggest that HGF exhibits therapeutic effects via anti-inflammation including antiapoptosis rather than epithelial cell proliferation in these inflammatory bowel disease models.     

Detection of the c-met proto-oncogene product in normal skin and tumours of melanocytic origin

The proto-oncogene c-met product (c-MET) is a receptor tyrosine kinase and functions as a receptor for hepatocyte growth factor (HGF). Although the function of c-MET has yet to be fully clarified, HGF stimulates the phosphorylation of tyrosyl residues on c-MET and triggers the signal transduction pathways, resulting in a contribution to the malignant progression of melanonocytes with synergic factors such as basic fibroblast growth factor and mast cell growth factor. Using immunohistochemical methods, we have studied the localization of c-MET in normal skin and various melanocytic tumours, c-MET was detected in keratinocytes, melanocytes, sebaceous cells, and other cells of the skin. In particular, basal melanocytes almost always showed nuclear labelling. Melanocytic naevi generally revealed predominantly nuclear staining of cells in the epidermis, whereas only a few cases showed a distinct cytoplasmic localization of c-MET in dermal naevus cells. The distribution pattern of c-MET in melanoma cells was basically similar to that of benign lesions, although the numbers tested were small. Cultured human melanoma cells also showed predominantly nuclear labelling, but were unresponsive to exogenous c-MET ligand HGF. Treatment with the glucosidase inhibitor castanospermine caused accumulation of protein at 220 kD, without diminishing the amount of normally-processed 190-kD c-MET. Although there was no significant difference in c-MET distribution between benign and malignant melanocytic lesions, it is suggested that malignant transformation of melanocytes may be associated with loss of response to HGF or other growth-regulating factors.     

Hepatoblastoma in an adult associated with c-met proto-oncogene imbalance

A rare case of hepatoblastoma in a 61-year-old Japanese housewife is described. This liver tumor mainly consisted of two tissue components: embryonal hepatocytes and primitive mesenchymal tissue. Fetal hepatocytes with alpha-fetoprotein production, gland formation, cartilage and osteoid were also found in a small portion. Molecular analysis by slot blot method revealed increased copy numbers of c-met and K-sam proto-oncogenes and cyclin D1 genes. These findings suggest that alterations of these oncogenes might play a role in the development of adult hepatoblastoma.     

蛇床子素通过c-met/PI3K/AKT途径提高顺铂对肺癌细胞的杀伤活性

目的探讨蛇床子素是否能提高顺铂对肺癌细胞的杀伤活性并研究其机制。方法 A549非小细胞肺癌细胞按对照组、蛇床子素组、顺铂组、蛇床子素+顺铂组及蛇床子素+顺铂+c-met质粒组进行分组后,MTT法检测A549细胞活力,Western blot实验检测A549细胞蛋白酪氨酸激酶(cmet)表达水平,磷脂酰肌醇3-激酶(PI3K)、丝氨酸/苏氨酸蛋白激酶(AKT)磷酸化水平及半胱天冬酶(caspases)活化水平的影响,流式细胞术检测A549细胞的凋亡。结果顺铂+蛇床子素组A549的细胞活力抑制率[(59.8±3.5)%]显著高于顺铂单治疗组[(16.9±1.2)%,P0.05]和蛇床子素+顺铂+c-met质粒组[(21.6±1.5)%,P0.05]。蛇床子素处理可诱导A549细胞c-met蛋白的下调并抑制A549细胞PI3K和AKT的磷酸化。顺铂+蛇床子素组对A549细胞的凋亡诱导率[(29.7±2.1)%]显著高于顺铂组[(7.8±0.9)%,P0.05]和蛇床子素+顺铂+c-met质粒组[(10.1±1.5)%,P0.05]。顺铂+蛇床子素组A549细胞的Caspase-9、Caspase-3活化水平显著高于顺铂组和蛇床子素+顺铂+c-met质粒组。结论蛇床子素通过下调c-met表达提高肺癌细胞对顺铂的敏感性。     

c-met慢病毒载体的构建及稳定转染骨髓间充质干细胞

构建肝细胞生长因子受体(c-met)慢病毒载体,并稳定转染骨髓间充质干细胞(BMSCs).将c-met连接到慢病毒载体GV358上,重组获得慢病毒载体GV358-c-met.再将该重组体与病毒辅助质粒共转染293T细胞,包装生产慢病毒并测定其滴度为2×108 TU/ml.将此慢病毒转染BMSCs,经嘌呤霉素筛药后,荧光显微镜下检测荧光阳性率达100%,且Western blot证实该细胞株表达c-met蛋白.成功构建了c-met慢病毒载体,并建立了稳定表达c-met的BMSCs.     

Sporadic ret-rearranged papillary carcinoma of the thyroid: a subset of slow growing,less aggressive thyroid neoplasms?

Despite the large amount of information accumulated on the role played by ret activation in the oncogenesis of papillary thyroid carcinoma (PTC), the biological and clinical significance of such activation ‘in vivo’ remains controversial. The aim of this study was to address some of the existing controversies by comparing two groups of unselected PTCs, one with and the other without ret rearrangement, with regard to several clinicopathological and biological features. Thirty-three PTCs were selected at random. ret rearrangement was found in eight cases (24·2 per cent) using Southern blot analysis. The mean age of the patients with tumours displaying ret rearrangement (28±3·1 years) was significantly lower than that of the patients harbouring cases that did not present rearrangement (45±2·9 years). The large majority of the tumours with ret rearrangement displayed a papillary or mixed follicular–papillary pattern and very low proliferative activity. ret rearrangement correlated significantly with decreased cytoplasmic expression of E-cadherin. No significant differences were found regarding the gender of the patients, tumour size, multicentricity, extrathyroidal growth, vascular invasion, lymphocytic infiltration, lymph node involvement or the expression of E-cadherin (membrane), c-erb-B2, c-met, Bcl-2, and vimentin. It is proposed that sporadic PTCs harbouring a ret rearrangement occur frequently as slow growing, papillary, or predominantly papillary tumours that do not usually progress towards less differentiated neoplasms representing what might be described as a Bonsai phenotype. © 1998 John Wiley & Sons, Ltd.     

胃癌组织中c-met、e2f-1和Ki-67的表达

目的 检测肝细胞生长因子受体c-met、转录因子e2f-1和Ki-67抗原在胃癌组织中的表达,探讨三者的相关性及与临床病理特征和预后的关系。方法 免疫组织化学染色法检测86例胃癌患者手术标本中c-met、e2f-1和Ki-67的表达,单因素与多因素法分析其与临床病理特征的关系及三者的相关性,Log rank检验分析其与患者预后的关系。结果 c-met、e2f-1和Ki-67在胃癌组织中均广泛表达。c-met的高表达与Ki-67高表达、生存期较短、肿瘤位置较高、淋巴结转移率较高、累及淋巴站较远及TNM分期较晚有关(P<0.05);e2f-1的低表达与肿瘤直径较大、TNM分期较晚、浸润较深、淋巴结转移率较高、累及淋巴站较远有关(P<0.05)。多因素分析显示,浸润深度、累及淋巴站、TNM分期和Ki-67表达是c-met表达的独立相关因素,而年龄和生存期是e2f-1表达的独立相关因素。Log rank检验显示,与术后生存相关的因素有c-met、e2f-1和Ki-67表达、累及淋巴站、肿瘤直径、肿瘤位置、淋巴结转移率、浸润深度和TNM分期。结论 c-met阳性表达的胃癌患者生存期显著缩短。e2f-1在早期胃癌中高表达,晚期胃癌的进展可能与e2f-1表达降低有关。     

c-met癌基因在乳腺癌增殖及血管生成中的作用

目的:探讨原癌基因c-met在乳腺癌增殖及微血管生成中的作用,为临床乳腺癌的病情预测及预后判断提供新的实验依据。方法:通过S-P免疫组织化学方法和微血管密度计数(MVD),检测75例乳腺浸润性导管癌和20例乳腺纤维腺瘤组织中原癌基因c-met的表达情况和微血管密度。结果:乳腺癌组织c-met阳性表达与组织学分级、淋巴结转移、肿瘤分期显著相关(P<0.05),而与年龄、病变部位、月经情况、雌激素水平、孕激素水平、肿瘤大小无关(P>0.05)。微血管计数与c-met阳性表达显著相关(P<0.01)。结论:c-met癌基因在乳腺癌中表达增强与乳腺癌肿瘤细胞增殖状态及微血管生成直接相关,可以成为判断乳腺癌预后的一个有价值的指标。     

脂质体槲皮素对Eca109/9706细胞增殖及血管内皮生长因子和c-met表达的影响

目的检测不同脂质体槲皮素对食管癌Eca109/9706细胞增殖及c-met和血管内皮生长因子(VEGF)表达的影响。方法MTT实验检测脂质体槲皮素和非脂质体槲皮素对Eca109/9706细胞生长的抑制率;免疫组织化学染色及免疫印迹检测脂质体槲皮素处理48h后Eca109/9706细胞中c-met,VEGF表达的改变。结果MTT检测表明,Eca109/9706的细胞生长抑制率依次为脂质体槲皮素(LQ2)组>脂质体槲皮素(LQ1)组>非脂质体槲皮素(nLQ)组>对照组(P<0.05);在人食管癌Eca109/9706细胞中,c-met及VEGF的免疫组织化学图像扫描灰度均值从高至低依次为:对照组>nLQ组>LQ1组>LQ2组(P<0.05)。c-met和VEGF的免疫印迹信号数值为各主带扫描灰度均值与各β-actin扫描灰度均值的比值,从高至低依次为:对照组>nLQ组>LQ1组>LQ2组(P<0.05)。结论脂质体槲皮素可抑制Eca109/9706细胞的增殖,其作用可能与降低c-met及VEGF的高表达有关。